Hydraulic feed control system for rotary drill

摘要

An hydraulic feed control system for feeding or retracting a rotary rock drill relative to the work in a selected one of four modes; namely, standard feed; regeneration feed; standard retract; and rapid retract. The system includes an hydraulic circuit controlling the feeding and retraction of feed cylinders connected to the drill; a pair of hydraulic pressure supply sources; and a pair of manipulative control valves. A primary one of the valves controls flow from one of the sources directly into the circuit; and the other control valve is selectively operable to direct flow from the other source through the primary valve into the circuit so as to combine the flow from both sources for the regeneration feed and rapid retract modes.